Water sprinkling devices are known which comprise an emitter tube of resiliently flexible material having a mounted inlet end and an unmounted outlet end. The arrangement is such that, with water flowing at a sufficient rate through the emitter tube from the inlet end to the outlet end and being discharged from the outlet end, hydraulic forces exerted by the flowing water on the emitter tube cause the outlet end continuously to move about, thus spreading the water. The basic construction is extremely simple. Apart from the flexible tube, there are no moving parts.
A problem experienced with the known sprinkling devices is that they do not evenly spread the water and are very sensitive to variations in the water supply pressure. The movement of the unmounted end is either erratic or in a single, fixed plane. When the movement is in a single, fixed plane, then obviously there is no efficient spreading of the water. It has also been found that, when the movement is erratic, despite the apparent random movement of the unmounted end, the water is not evenly distributed over the area irrigated. In other words, there are spots in the area irrigated that receive relatively little water, and other spots which receive relatively much water.
Attempts have been made to influence the movement of the emitter tube by fitting flow deflecting devices to the unmounted end thereof. Examples of such flow deflecting devices can be found in U.S. Pat. Nos. 2,930,531 and 2,999,644. All these attempts have failed to solve the problem.
It is an object of the present invention to provide a sprinkling device of the kind in question, which is less sensitive to variations in pressure and in which the liquid is more evenly spread over the area being irrigated.